Abstract

ZnO junction light-emitting diodes(LEDs) were fabricated on -plane substrates by plasma-assisted molecular beam epitaxy. Gas mixture of and was used as the -type dopant, by which the double-donor doping of can be avoided significantly. The fabricated -type ZnO layers have a higher hole density and carrier mobility. The LEDs showed a very good rectification characteristic with a low threshold voltage of even at a temperature above . The LEDs can even emit intensive electroluminescence in the blue-violet region at the temperature of . The blue-violet emission was attributed to the donor-acceptor pair recombination at the -type layer of the LED.

Received 26 May 2006Accepted 21 December 2006Published online 26 January 2007

Acknowledgments:

This work is supported by the “863” High Technology Research Program in China, under Grant No. 2001AA311120, the Key Project of National Natural Science Foundation of China under Grant No. 60336020, the Innovation Project of Chinese Academy of Sciences, the National Natural Science Foundation of China under Grant Nos. 60278031, 60376009, 50402016, 60506014, and 60501025, the State Natural Science Foundation—Outstanding Oversea Chinese Young Scholar Foundation, No. 60429403, and the Direct Allocation Grant of Research Grants Committee of Hong Kong, No. DAG04/05.SC24.